The application of inflatable devices to many uses is quite common in many fields. They are used in buildings and shelters of various types, particularly as brace structures which are erected by inflation with compressed air, or other high pressure fluid. They are also highly useful for their shock absorbing properties, and are thus employed as vehicle bumpers, guard rails and the like. An important recent application of inflatable belts or tubes, as in vehicle passenger passive restraint systems, and particularly in systems employing inflatable safety belts. The safety belt system is of such construction that the belt device is inflated with compressed air to provide a cushioned restraint to the passenger, particularly automatically, under abnormal conditions, and it is highly advantageous that the belt webbing itself be directly inflated with the compressed air. However, when the conventional restraint device of tubular construction is inflated with a pressurized fluid, it is urged to expand or extend into a linearly extending configuration. This tendency is highly undesirable, since in order to optimumly confine and restrain the vehicle passenger, the inflated belt should curve in a manner to conform to and tightly and snuggly engage the body of the passenger in the area of the restraint belt. Moreover, the inflatable belt is of great advantage when formed of a soft, highly flexible fabric, so as to be easily shaped to the contour of the passenger's body.